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Biomedical subjects

H Knisatschek

Publications and source records attributed to H Knisatschek.

8 recordsLinked to original sources

[Chronic progressive spinobulbar spasticity (primary lateral sclerosis)].

This paper presents an account of chronic-progressive Spinobulbar Spasticity (SBS) or Primary Lateral Sclerosis (PLS), a rare syndrome involving degeneration of the upper motoneuron, on the basis of 6 clinically examined cases. Individuals of both sexes can be affected. Onset of the syndrome occurs around the age of 54, but may sometimes be before 50. Early symptoms of the disease are spasticity on one leg and disturbance of motor skills in one hand. The symptoms generalize within two to three years into tetraspasticity accentuated in the legs, accompanied by pseudo-bulbar dysarthria and dysphagia, which, however, may also be present at the onset of the disease. Compulsive laughing and crying, optokinetic disturbances and facial stiffness develop as additional, though inconstant symptoms. Disease courses of 25 years were observed. Therapy is symptomatic. Fasciculation and muscular atrophy, which would indicate a transition to Amyotrophic Lateral Sclerosis (ALS), were not observed even if the disease was of longstanding. SBS differs from spastic spinal paralysis by virtue of its greater mean age of incidence, its tetraspasticity in conjunction with pseudobulbar signs, and-so far as can be established to date-its apparent non-hereditariness. An influence of exotoxic factors has not been demonstrated so far. The clinical syndrome results from a selective degeneration of the corticospinal and cortico-bulbar tracts up to the motor cortex, where loss of original pyramidal cells has been shown to occur (Pringle et al., 1992). The paper includes a survey of the clinical and neuropathological findings in cases of SBS published so far. Extensive anamnestic and clinical records including TCMS-studies, PET and NMR-CT scans performed in the parasagittal plane are essential for early diagnosis of the syndrome.

Aged↗

Specific inhibition of post proline cleaving enzyme by benzyloxycarbonyl-Gly-Pro-diazomethyl ketone.

N-Benzyloxycarbonyl-Gly-Pro-diazomethyl ketone (Z-Gly-Pro-CHN2) was synthesized and tested as inhibitor of the post proline cleaving enzyme from bovine brain. The compound was found to inactivate the enzyme completely and irreversibly at low concentrations (0.3 microM) without affecting other proteolytic enzymes such as post proline dipeptidyl aminopeptidase, pyroglutamate aminopeptidase or trypsin. Substrates of post proline cleaving enzymes such as luliberin (LH-RH; pyroGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2) and Benzyloxycarbonyl-Gly-Pro-Ala protected the enzyme from the reaction with Z-Gly-Pro-CHN2. Thus, Z-Gly-Pro-CHN2 seems to be an active site directed, specific inhibitor of post proline cleaving enzyme. When administered intraperitoneally to rats, this inhibitor (8 mg/kg) completely inactivated the post proline cleaving enzyme in all tissues studied including brain. Therefore, Z-Gly-Pro-CHN2 should be a valuable tool for studies on the physiological function of this enzyme within the metabolism of neuropeptides.

Animals↗

Ontogenesis of neuropeptide degrading enzymes in the mouse brain.

The ontogenesis of neuropeptide degrading enzymes was studied in the mouse brain, from the 10th gestational day up to adulthood. Two activities were followed: the pyroglutamate aminopeptidase and the post-proline cleaving enzyme, using either TRH or specific fluorgenic peptides as substrates. In the hypothalamus as well as in cerebral hemispheres, the specific activities of both enzymes was highest on the 13th fetal day and decline thereafter until the 20-22nd post-natal day, with a plateau around birth. In contrast, a classical peptidase, the leucyl-arylamidase increased only in fetal life, and reached the adult level before birth.

Aging↗

Characterization of "thyroliberin-deamidating enzyme" as a post-proline-cleaving enzyme. Partial purification and enzyme-chemical analysis of the enzyme from anterior pituitary tissue.

An enzyme which catalyzes the deamidation of thyroliberin (TRF; less than Glu-His-Pro-NH2) has been purified 110-fold from extracts of bovine anterior pituitary by ammonium sulfate fractionation, ion exchange chromatography on DEAE-cellulose, and gel filtration. This enzyme of 76,000 molecular weight (as estimated by gel filtration) exhibits maximal activity at neutral pH (optimum pH 7.4 to 7.6) in buffers of high ionic strength supplemented with thiol-protecting agents. As indicated by the strong inhibition of the enzymatic activity by N-ethylmaleimide and Hg2+, as well as by the extreme sensitivity toward diisopropyl fluorophosphate, -SH, and -OH residues apparently represent essential functional groups of the enzyme. The stereospecific deamidation of TRF (Km = 4.1 . 10(-4) M) is inhibited competitively by TRF analogues which contain proline or by the proline containing biologically active peptides luliberin (LH-RF), oxytocin, vasopressin, angiotensin II, and Substance P. TRF analogues without proline or peptide amides without proline are ineffective. This enzyme cleaves the appropriate Pro-X bonds in luliberin, angiotensin II, pyroGlu-His-Pro-Gly-NH2, and the collagenase substrate Z-Gly-Pro-Leu-Gly-Pro. Thus, it may be characterized as a post-proline-cleaving enzyme.

Amidohydrolases↗

Effects of an ACTH/MSH(4-9) analog (HOE 427) on the sleep EEG and nocturnal hormonal secretion in humans.

The synthetic ACTH/MSH(4-9) analog HOE 427 ("ebiratide"), which is behaviorally the most potent ACTH-derived peptide but which is devoid of endocrine activity, was administered intravenously in a pulsatile mode 4 times (120 micrograms each) at 2200, 2300, 2400 and 0100 to study its effect on the sleep EEG and on concomitant hormonal secretion of cortisol and growth hormone. In comparison to placebo, the peptide produced signs of general activation associated with specific deteriorating effects on the quality of sleep. Sleep onset latency and intermittent wakefulness were increased, slow wave sleep was reduced, but only during the first 3 hours of the sleep period. The nocturnal secretory patterns of cortisol and growth hormone were unaffected by HOE 427. These effects are different from those reported in similar studies in which corticotropin-releasing hormone (CRH) was applied in humans, and they suggest that peripherally administered neuropeptides have specific nonendocrine behavioral effects.

Adrenocorticotropic Hormone↗